An aircraft is propelled by a number of jet engines each housed in a nacelle which also accommodates a collection of auxiliary actuating devices associated with the operation thereof and performing various functions when the jet engine is operating or stationary. These auxiliary actuating devices particularly comprise a mechanical system for actuating thrust reversers.
A nacelle generally has a tubular structure comprising an air inlet in front of the jet engine, a mid-section intended to surround a fan of the jet engine, and a rear section accommodating thrust reversal means and intended to surround the combustion chamber of the jet engine, and is generally terminated by an exhaust nozzle whose outlet is situated downstream of the jet engine.
Modern nacelles are often intended to accommodate a turbofan jet engine designed, via the blades of the rotating fan, to generate a hot air stream (also known as primary stream) from the jet engine combustion chamber.
A nacelle generally has an outer structure, termed Outer Fixed Structure (OFS), which, together with a concentric inner structure, termed Inner Fixed Structure (IFS), comprising an inner panel surrounding the actual structure of the jet engine to the rear of the fan, defines an annular flow duct, also termed flow path, aimed at channeling a cold air stream termed secondary steam, which flows around outside the jet engine. The primary and secondary streams are ejected from the jet engine via the rear of the nacelle.
Certain equipment of the jet engine conduct highly pressurized fluids. In the event of untimely breakage of this equipment, the inner panel is subjected to a high excess pressure which can lead as far as the destruction of a part of said panel and/or of the equipment housed in this environment. To avoid this destruction, it is commonly accepted to install one or more excess pressure flaps in the rear part of the inner panel of the outer structure, at the outlet of the annular duct, the gas flow rate constituting the excess pressure then being theoretically discharged directly to the outside of the nacelle.
Nevertheless, the gas flow rate generated by the explosion produced in the jet engine compartment can be expelled only after having travelled the whole way to the nearest excess pressure flap. Now, it has been found in practice that this distance had the effect of greatly limiting the benefit of integrating such excess pressure flaps, insofar as the structure and/or the equipment could suffer before the excess pressure is discharged. In certain cases, it has even been found that these excess pressure flaps did not play any role.
It is known from document U.S. Pat. No. 4,825,644 to form exhaust means in the inner panel, these exhaust means comprising at least one excess pressure flap equipped with spacing means for ensuring a minimum discharge flow rate to the outside in the event of untimely excess pressure, said spacing means being produced with the aid of at least one strut equipped with locking means designed to lock said strut in its spacing position in the event of excess pressure requiring the opening of the excess pressure flap. Consequently, the untimely excess pressure occurring in the jet engine compartment is immediately discharged inside the annular duct via the exhaust means, and cannot therefore cause the destruction of the inner panel and/or the surrounding equipment.